Disc Brake and Set of Brake Pads

ABSTRACT

A disc brake for a vehicle, in particular for a commercial vehicle, is provided. The disc brake includes at least one application-side brake pad and a back-side brake pad held in a form-fitting manner in a brake carrier. At least the application-side brake pad is provided with at least one pad-retaining spring which is supported at least on one brake carrier horn of the brake carrier and exerts a radially outwardly acting tensile force on the brake pad.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.14/939,748, filed Nov. 12, 2015, the disclosure of which is expresslyincorporated by reference herein.

The present invention relates to a disc brake and to a set of brake padsfor a disc brake, and in particular to brake pad retaining devicearrangements.

Disc brakes of this type are used in particular in commercial vehiclesand are frequently provided with pneumatic actuation. One embodiment ofthe brake caliper of disc brakes of this type is in the form of asliding caliper and is used, for example, in a tight construction spacein the vicinity of an adjacent wheel rim.

A sliding brake caliper is customarily connected to a supporting brakecarrier via two bearing struts which are designed as fixed and movablebearings. The brake pads of the disc brake are guided displaceably inthe brake carrier and are typically held in a spring-loaded manner inpad slots in the brake carrier by a pad-retaining clip.

In the case of disc brakes, in particular in the case of disc brakeswith only one force introduction element, the design may induce anuneven wear of the brake pads. The brake pads may not wear in paralleleither in the radial direction or in the circumferential direction withrespect to a plane of the pad carrier plates thereof, which is referredto as radial or tangential wear.

An example of a spring-loaded pad-retaining clip is described in GermanUtility Patent No. DE 20 2008 013 446 U1.

The documents International Patent Publication No. WO 2013/143993 A1,German Patent Publication No. DE 10 2012 002 734 A1 and U.S. Pat. No.8,540,061 B1 illustrate brake pad retaining systems.

Against the background of these solutions, there continues to be aconstant requirement for an extended service life of brakes and brakecomponents with a simultaneous reduction in costs.

The invention is therefore based on the object of providing an improveddisc brake.

It is a further object to provide an improved set of brake pads for adisc brake.

The invention achieves the first object by providing a disc brake inwhich the application-side brake pad has at least one associatedpad-retaining spring supported on at least one brake carrier horn abrake carrier and exerting a radially outwardly acting tensile force onthe brake pad.

The further object is achieved by providing a set of brake pads for sucha disc brake for a vehicle, in which the application-side brake pad hasat least one pad-retaining spring with at least one pressure sectionthat protrudes laterally over one end of the application-side brakepad's back plate.

Accordingly, a disc brake for a vehicle, in particular for a commercialvehicle, includes a brake disc with a brake disc rotational axis, atleast one application-side brake pad and a back-side (also known asreaction-side) brake pad, a brake carrier which accommodates the atleast two brake pads in a respective pad slot, wherein the at least oneapplication-side brake pad is held in a form-fitting manner in theassociated pad slot, and a brake caliper which straddles the brake discand is designed as a sliding caliper. The application-side brake pad isprovided with at least one pad-retaining spring which is supported atleast on one brake carrier horn of the pad slot of the brake carrier andexerts a radially outwardly acting tensile force on the brake pad.

The radially outwardly acting tensile force makes it possible for thebrake pad to be pulled into the form-fitting holder thereof, as a resultof which a reduction in oblique wear is advantageously made possible.

The production of the tensile force is possible by an advantageouslysimple arrangement with at least one pad-retaining spring which issupported on a brake carrier horn of the pad slot after the brake padhas been fitted.

In one embodiment, the at least one application-side brake pad is inengagement in a form-fitting manner via a pad back plate with contoursof brake carrier horns in the pad slot of the brake carrier. Fixing ofthe application-side brake pad in both radial directions with respect tothe brake disc rotational axis is therefore advantageously madepossible.

For this purpose, in a further embodiment, it is provided that thecontours of the brake carrier horns correspond with contours of the padback plate, wherein undercut surfaces of the contours of the brakecarrier horns are in each case in engagement in a play-free manner withundercut surfaces of projections of the pad back plate.

In a further embodiment, the at least one pad-retaining spring isattached to the pad back plate. A compact brake pad is thereforecreated.

The at least one pad-retaining spring can be attached here on an upperside of the pad back plate, which permits a saving on space.

In yet another embodiment, the at least one pad-retaining springcomprises a central section; arms; pressure sections and transitionsections, wherein the central section is attached on the upper side ofthe pad back plate, wherein the transition sections bear on the upperside of the pad back plate, and the pressure sections at one end in eachcase of the upper side of the pad back plate protrude laterally from thepad back plate. Effective and simple pretensioning of the pad-retainingspring can thus be produced. The pad-retaining spring can be, forexample, a flat spring steel, from which said pad-retaining spring isproduced as a punched and bent part.

In an alternative embodiment, the at least one pad-retaining springcomprises a central section; arms; pressure sections and intermediatesections, wherein the central section is attached by at least onefastening element to the pad back plate, wherein the pressure sectionsat one end in each case of the upper side of the pad back plate protrudelaterally from the pad back plate. It is therefore made advantageouslypossible to use existing fastening elements without or only with minoramendments.

For this purpose, the at least one fastening element can be ofclamp-like design and have a transverse section which, in the mountedstate of the pad-retaining spring, extends through an opening in the padback plate, wherein the pad-retaining spring is arranged between the atleast one fastening element and an upper side of the pad back plate.This is advantageous since the pad-retaining spring is thereby attachedcaptively to the pad back plate of the brake pad. A further advantagehere is a clearance of the central part of the pad-retaining springbetween the fastening element and the pad back plate, as a result ofwhich uniform loading of the pad-retaining spring can be achieved.

In a further embodiment, the pad-retaining spring has at least one slitthrough which a section of the at least one fastening element extends.For example, existing punching tools can thus be used for slits ofpad-retaining springs. In addition, it is possible for pad-retainingspring and fastening element to be kept captively together.

In yet another embodiment, the pad-retaining spring has at least onefurther slit through which a guide projection of the pad back plateextends. In this manner, the pad-retaining spring can advantageously bekept centered on the upper side of the pad back plate and can be guidedin the possible longitudinal movements thereof in such a manner that acontact connection of the pressure sections with the brake carrier hornsremains ensured.

If at least one of the pressure sections is supported on the at leastone brake carrier horn of the pad slot of the brake carrier, anadvantageously simple tensile force is produced on the brake pad, withno additional measures being required at the brake carrier.

In an alternative embodiment, the at least one pad-retaining spring isattached on an upper side of the pad back plate by at least one springholder. An advantageous saving on weight is therefore made possible.

In a further embodiment, the at least one spring holder has at least oneretaining element, wherein the at least one pad-retaining spring isarranged and held in a pretensioned manner between the at least oneretaining element and the upper side of the pad back plate. This resultsin a simple production of pretensioning.

In yet another embodiment, the at least one pad-retaining springcomprises at least one central section, transition sections, at leastone pressure section and at least one bearing section.

In a further embodiment, the at least one bearing section rests on theupper side of the pad back plate, and the at least one pressure sectionprotrudes laterally from the pad back plate at an end of the upper sideof the pad back plate. This results in an advantageously compact design.

For advantageously simple production of a tensile force which acts onthe brake pad, the at least one pressure section is supported on the atleast one brake carrier horn of the pad slot of the brake carrier.

In a further embodiment, the at least one retaining element is designedas a roller, in particular cable roller. A roller design of this typehas the advantage of laterally guiding the pad-retaining spring.

In a preferred embodiment, it is provided that the at least onepad-retaining spring is produced from a spring wire. The pad-retainingspring is therefore simple to produce.

A further preferred embodiment provides two such pad-retaining springsat each end of the upper side of the pad back plate. This results inimproved production of tensile force.

A set of brake pads for an above-described disc brake for a vehicle, inparticular for a commercial vehicle, comprises the at least oneapplication-side brake pad and at least one back-side brake pad. Theapplication-side brake pad has at least one pad-retaining spring with atleast one pressure section, wherein the at least one pressure sectionprotrudes laterally over one end of an upper side of a pad back plate ofthe application-side brake pads.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a first embodiment of a disc brakeaccording to the invention;

FIGS. 2-4 show partial views of a brake carrier of the disc brakeaccording to the invention according to FIG. 1 with a brake padaccording and embodiment of the invention;

FIGS. 5-7 show views of the brake carrier according to FIGS. 2-4;

FIGS. 8-9 show views of a second embodiment of the disc brake accordingto the invention;

FIGS. 10-11 show enlarged partial views of the second embodiment of thedisc brake according to FIGS. 8-9;

FIGS. 12-13 show partial views of a third embodiment of the disc brakeaccording to the invention;

FIG. 14 shows a perspective view of a pad back plate of a brake pad ofthe third embodiment according to FIGS. 12-13;

FIG. 15 shows a perspective view of a pad-retaining spring of theembodiment according to FIGS. 12-13;

FIG. 16 shows a perspective view of a fastening element of thepad-retaining spring according to FIG. 15;

FIGS. 17-18 show partial views of a fourth embodiment of the disc brakeaccording to the invention;

FIG. 19 shows a perspective view of a pad back plate of a brake pad ofthe fourth embodiment;

FIG. 20 shows a perspective view of a pad-retaining spring of theembodiment according to FIGS. 17-18; and

FIGS. 21-22 show a perspective view and a cross-section elevation view,respectively, of a pad back plate of a brake pad and a pad-retainingspring of a fifth embodiment of the disc brake according to theinvention.

Disc brakes of this type are used in particular in commercial vehiclesand are frequently pneumatically-actuated. One embodiment of the brakecaliper of disc brakes of this type is in the form of a sliding caliperand is used, for example, in a constricted construction space in thevicinity of an adjacent wheel rim.

Terms such as “top”, “bottom”, “right”, “left”, etc., relate toorientations and arrangements in the figures.

DETAILED DESCRIPTION

Disc brakes of this type are used in particular in commercial vehiclesand are frequently pneumatically-actuated. One embodiment of the brakecaliper of disc brakes of this type is in the form of a sliding caliperand is used, for example, in a constricted construction space in thevicinity of an adjacent wheel rim.

FIG. 1 shows a perspective view of a first embodiment of a disc brake 1according to the invention, for example a pneumatic disc brake 1. FIGS.2 to 4 illustrate partial views of a brake carrier 5 of the disc brake 1according to the invention according to FIG. 1 with a brake pad 3according to the invention. For the sake of better clarity, a brake disc2 is not shown in FIG. 1, but is easily imaginable, for example as shownin FIG. 9. FIG. 2 shows a top view of a friction pad 3 b of the brakepad 3 in a brake carrier 5. FIG. 3 illustrates forces 11, 12 acting onthe brake pad 3. FIG. 4 shows an enlarged illustration of one side ofthe brake pad 3 in engagement with a brake carrier horn 5′a.

The disc brake 1 is, for example, part of the brake system of a vehicle,in particular of a commercial vehicle, and comprises the brake disc 2having a brake disc rotational axis 2 a, and two brake pads 3 which arearranged on both sides of the brake disc 2. Of the two brake pads 3,only an “application-side” brake pad 3 is shown here. The other“back-side” brake pad is easily imaginable, and may be identical to, orshaped differently from, the application-side brake pad. Furthermore,the disc brake 1 comprises the brake carrier 5, a brake caliper 6 and anapplication device (not shown).

The brake pad has a pad back plate 3 a, on which the friction pad 3 b isattached. The brake pads 3 are each accommodated in the brake carrier 5in a pad slot 15, 16 (also see FIGS. 5, 6) between in each case twobrake carrier horns 5 a, 5′a; 5 b, 5′b and are held in the brake carrier5. A pad-retaining clip (not shown) is positioned above, i.e., radiallyoutboard of, the brake pads 3. At least the brake pad 3 is guideddisplaceably in the direction of the brake disc rotational axis 2 a inthe associated pad slot 15. During forward travel of the associatedvehicle in a positive x direction, the brake disc 2 rotates about thebrake disc rotational axis 2 a thereof in a main direction of rotation10 (FIG. 3). That side of the brake caliper 6 which is located on theleft of FIG. 1 is therefore referred to as the entry side and that sideof the brake caliper 6 which is located on the right is referred to asthe exit side. Accordingly, the brake carrier horns 5′a, 5′b arereferred to as entry-side brake carrier horns 5′a, 5′b and the oppositebrake carrier horns 5 a, 5 b are referred to as exit-side brake carrierhorns 5 a, 5 b. Unless stated otherwise, components and assemblies whichare assigned to the entry side are identified below by an apostrophe atthe respective reference sign.

The brake caliper 6 is designed here as a sliding caliper and has anapplication section 6 a and a back section 6 b which are connected toeach other at both ends in the direction of the brake disc rotationalaxis 2 a via connecting sections 6 c, 6′c. The application section 6 aand the back section 6 b are respectively arranged here on one side ofthe brake disc 2 in a manner parallel thereto, wherein the connectingsections 6 c extend in the y direction parallel to the brake discrotational axis 2 a. The application section 6 a and the back section 6b together with the connecting section 6 c form an opening over thebrake disc 2 with the brake pads 3 for access thereto duringinstallation, exchange and maintenance work.

The application section 6 a of the brake caliper 6 receives theapplication device of the disc brake 1. The application device servesfor actuating the disc brake 1 and can have, for example, a pivotedbrake lever with a compressed air cylinder. This is not describedfurther here.

That side of the disc brake 1 on which the application section 6 a ofthe brake caliper 6 is arranged together with the application device isreferred to below as the application side ZS. The other side of the discbrake 1, on which the back section 6 b of the brake caliper 6 isarranged, is referred to below as the back side RS, which is also calledthe reaction side. These terms “application side” and “back side” andother designations referring thereto are conventional and are used forbetter orientation.

The brake pad 3 with the pad back plate 3 a, which is located on theapplication side ZS, is thus referred to as the application-side brakepad 3, and the opposite brake pad to the latter is referred to in acorresponding manner as back-side brake pad.

The application-side brake pad 3 is acted upon by the application deviceduring braking operations with an application force in the direction ofthe brake disc rotational axis 2 a. The back-side brake pad, which isnot shown but is imaginable, is accommodated in the back section 6 b ofthe brake caliper 6 and, in the case of this disc brake 1 with thesliding brake caliper 6 does not have any movements relative to the backsection 6 b.

The application-side brake pad 3 is provided with a pad-retaining spring7 on an upper side 3 d of the pad back plate 3 a. The pad-retainingspring 7 (FIG. 2) comprises a central section 7 a; arms 7 b, 7′b;pressure sections 7 c, 7′c and transition sections 7 d, 7′d.

The central section 7 a is fastened to the upper side 3 d of the padback plate 3 a approximately in the center of the upper side 3 d andextends to both sides in the longitudinal direction of the pad backplate 3 b (i.e. parallel to the brake disc 2 in the fitted state of thebrake pad 3) in each case to a length which approximately corresponds toa quarter of a length of the pad back plate 3 d in the longitudinaldirection. The fastening of the central section 7 a can take place, forexample, by welding, rivets, screws and the like.

A respective transition section 7 d, 7′d via which a respective arm 7 b,7′b is connected to the central section 7 a is attached to each end ofthe central section 7 a. The transition sections 7 d, 7′d are of curveddesign, wherein said transition sections are shaped convexly towards theupper side 3 d of the pad back plate 3 a. In this manner, the transitionsections 7 d, 7′d each rest in linear contact on the upper side 3 d ofthe pad back plate 3 a. In this example, in the fitted state of thebrake pad 3, the linear contact runs parallel to the brake discrotational axis 2 a. Of course, other contact forms are also possible,for example single-point contact, multi-point contact, multilinecontact, etc.

The convex transition section 7 d, 7′d span the central section 7 a, asa result of which said transition sections are pressed onto the upperside 3 d by means of the spring force of the central section 7 a.

Each transition sections 7 d, 7′d merges into a respective arm 7 b, 7′b.Each arm 7 b, 7′b extends as far as a respective end of the upper side 3d of the pad back plate 3 a and rests with its respective end on thelatter when the brake pad 3 is not fitted.

A respective pressure section 7 c, 7′c which protrudes in each case overthe associated end of the upper side 3 d in the longitudinal directionof the pad back plate 3 a and is pressed onto the upper side 3 d of thepad back plate 3 a by the spring force of the central section 7 a, ofthe transition sections 7 d, 7′d and of the arms 7 b, 7′b is attached toeach free end of an arm 7 b, 7′b.

Each pressure section 7 c, 7′c is of convex design in such a manner thatthe convex side thereof faces downwards towards the pad back plate 3 a.A rounding of the pressure sections 7 c, 7′c is smaller than a roundingof the transition sections 7 d, 7′d.

In this example, a width of the pad-retaining spring 7 is constant andcorresponds here approximately to a thickness of the pad back plate 3 a.Width and thickness run in the direction of the brake disc rotationalaxis 2 a. Of course, the width of the pad-retaining spring 7 can alsorun differently with respect to the pad back plate 3 a or/andnon-constantly.

The application-side pad slot 15 is delimited on both sides by the brakecarrier horns 5 a, 5′a and in this embodiment is closed on the lowerside thereof by a strut 5 d (the strut 5 d may be omitted). Each brakecarrier horn 5 a, 5′a has, approximately in the center thereof in adirection perpendicular to the brake disc rotational axis 2 a, arespective lug 5 c, 5′c which protrudes inwards into the pad slot 15 andhas rounded corners. An undercut 4, 4′ is formed below each lug 5 c,5′c, said undercut being formed into the respective brake carrier horn 5a, 5′a in each case outwards, i.e. starting from the pad slot 15 in aplane parallel to the brake disc 2, and in each case forming a contourwith the lug 5 c, 5′c. Each undercut 4, 4′ runs below each lug 5 c, 5′cinto the respective brake carrier horn 5 a, 5′a initially parallel tothe strut 5 d. Said respective contour then runs in each case at a rightangle in the brake carrier horn 5 a, 5′a downwards as far as a restwhich, for its part, extends at a right angle towards the inner side ofthe pad slot 15 over a distance which approximately corresponds to thelength of the undercut 4, 4′ below each lug 5 c, 5′c. Said rests areconnected by the strut 5 d, wherein an upper side of the struts 5 d isarranged lower, i.e. further towards the brake disc rotational axis 2 a,than the surfaces of the rests. In alternative embodiments, the restsmay be omitted if equivalent rest surfaces between the brake pad backplate 3 a and the lugs 5 c, 5 c′ are located at a higher location, forexample, at flat surfaces machined into the top of the lugs 5 c, 5 c′and into the back plate in the region directly above the machined flats.

Each side of the application-side pad back plate 3 a interacts with arespective brake carrier horn 5 a, 5′a and has a contour whichcorresponds to the respective contour of the associated brake carrierhorn 5 a, 5′a. In other words, the shape of each lug 5 c, 5′c is formedinto the associated side of the pad back plate 3 a, wherein a respectiverectangular projection 3 c, 3′c of the pad back plate 3 a is formed,said projection corresponding with the respective associated undercut 4,4′ of a brake carrier horn 5 a, 5′a. In this manner, theapplication-side brake pad 3 is accommodated by the pad back plate 3 ain the application-side pad slot 15 in the contours with the lug 5 c,5′c and with the undercut 4, 4′ in a form-fitting manner such that theapplication-side brake pad 3 is guided displaceably in the direction ofthe brake disc rotational axis 2 a, but is fixed in the perpendiculardirection to the brake disc rotational axis 2 a. Only the end regions ofthe lower side of the application-side pad back plate 3 a rest here onthe respective rests at the ends of the strut 5 d.

In FIG. 2, the brake pad 3 is inserted into the pad slot 15 of the brakecarrier 5. This takes place first of all by inserting the brake pad 3radially into the intermediate space between the pad slots 15, 16 (FIGS.5, 6).

In this embodiment, during installation the pad-retaining spring 7 isfirst of all supported on a brake carrier horn 5 a, 5′a. The brake pad 3is thereby aligned to slide into the undercuts 4, 4′ of the brakecarrier 5. Subsequently, the brake pad 3 is fixed in the pad slot 15 ofthe brake carrier 5 and can be pushed in the axial direction, i.e., inthe direction of the brake disc rotational axis 2 a, into the workingposition thereof by the brake caliper 6.

The contours of the sides of the pad back plate 3 a of the brake pad 3come into engagement here with the contours of the lugs 5 c, 5′c and ofthe undercuts 4, 4′ and form a form-fitting contact. The convex sides ofthe pressure sections 7 c, 7′c of the pad-retaining spring 7 are then ineach case in contact by the contact sections 9, 9′ thereof for restingon rest sections 8, 8′ (FIG. 3) on the upper sides of the brake carrierhorns 5 a, 5′. The pad-retaining spring 7 is supported here on theapplication-side brake carrier horns 5 a, 5′a and is tensioned upwardscounter to the spring force of the pad-retaining spring 7.

The pad-retaining spring 7 which is tensioned on both sides in thismanner exerts a tensile force on the brake pad 3 outwards in the radialdirection in a manner pointing away from the brake disc rotational axis2 a. This results in a play-free contact of the brake pad 3 against thebrake carrier horns 5 c, 5′c by undercut surfaces 14, 14′ of the brakepad projections 3 c, 3′c on undercut surfaces 13, 13′ of the lower sidesof the carrier horn lugs 5 c, 5′c.

In order to reduce tangential oblique wear (over the longitudinal side,i.e. the long side of the brake pad 3), in particular in the case ofsingle-brake application spindle embodiments of the disc brake 1, africtional force 11 is produced on the entry-side undercut surface 13′,14′ by lever kinematics. The latter use a lever arm 11 a to generate atorque about a pivot point 10 a. The pivot point 10 a lies in contacthere between an upper corner edge of the exit-side projection 3 c and alower corner edge of the lug 5 c of the exit-side brake carrier horn 5 abetween the undercut surfaces 13 and 14.

Said torque acts counter to an entering torque (force 12 with a leverarm 12 a—a known effect which allows the entering side of the frictionpad 3 b to be worn more severely by support of the pad back plate 3 a ofthe brake pad 3 on the exit-side brake carrier horn 5 a) and thereforecompensates for a part of the (tangential) oblique pad wear.

For optimum use of this effect, the undercut surfaces 13, 14; 13′, 14′are designed in such a manner that they are in engagement in a play-freemanner in the fitted state of the brake pad 3.

FIGS. 5 to 7 illustrate views of the brake carrier 5 according to FIGS.2 to 4 of the disc brake 1 according to the invention according to FIG.1.

FIG. 5 shows a perspective illustration of the brake carrier 5, as seenfrom the application side ZS (FIG. 1) looking at a fastening side 5 e ofthe brake carrier 5. The application-side pad slot 15 with the brakecarrier horns 5 a, 5′a and the lugs 5 c, 5′c protruding into the padslot 15 can clearly be seen. The back-side pad slot 16 has brake carrierhorns 5 b, 5′b without lugs, which are connected by a strut 5 f parallelto the strut 5 d.

FIG. 6 illustrates the exit-side undercut 4 in enlarged form in aperspective view.

FIG. 7 shows an elevation view of the fastening side 5 e of the brakecarrier 5. The brake carrier 5 is attached by the fastening side 5 ethereof to positionally fixed fastening sections of the vehicle.

FIGS. 8 and 9 show views of a second embodiment of the disc brake 1according to the invention. A partial sectional view is illustrated inFIG. 8, wherein the section runs in a plane through the brake carrier 5parallel to a brake disc plane. FIG. 9 shows a perspective view of thesecond embodiment of the disc brake 1. FIGS. 10 and 11 show enlargedpartial views of the second embodiment of the disc brake 1 according toFIGS. 8 and 9.

In this second embodiment, the components of the disc brake 1 areidentical to those in the first embodiment except for the brake pad 3.Therefore, only the differences of the brake pad 3 will be dealt withbelow.

The application-side brake pad 3 also has a pad back plate 3 a with afriction pad 3 b in this embodiment. The pad back plate 3 a is providedwith contours which correspond with contours of the lugs 5 c, 5′c andundercuts 4, 4′. This has already been described above in conjunctionwith the first embodiment.

The pad back plate 3 a is formed in the side regions thereof on theupper side 3 d with a respective spring holder 17, 17′ for at least onepad-retaining spring 70, 70′ in each case. Each spring holder 17, 17′comprises a projection 17 a, 17′a which protrudes upwards from the padback plate 3 a. Each projection 17 a, 17′a is plate-like and protrudesupwards in approximately double the thickness of the pad back plate 3 a.An expansion of each projection 17 a, 17′a in the longitudinal directionof the pad back plate 3 a likewise corresponds approximately to doublethe thickness of the pad back plate 3 a. Each projection 17 a, 17′a isarranged offset at a distance from each side of the pad back plate 3 atoward the center thereof in the longitudinal direction thereof, whereinsaid distance approximately corresponds to the thickness of the pad backplate 3 a.

The back surface, which faces towards the application side ZS, of eachprojection 17 a, 17′a is aligned with the back surface of the pad backplate 3 a which faces towards the application side ZS.

A respective retaining element 18, 18′ is attached in the center of theside facing towards the friction pad 3 b of each projection 17 a, 17′a.In this embodiment, said retaining element 18, 18′ is a roller which isfixedly attached or is rotatable about an axis running parallel to thebrake disc axis 2 a. Said roller can be designed, for example, as acable roller. The upper side 3 d of the pad back plate 3 a is providedin the region below each retaining element 18, 18′ with a respectivecurved recess which corresponds with a roller diameter of the retainingelement 18, 18′ and with respect to which each retaining element 18, 18′is arranged at a distance.

A respective pad-retaining spring 70, 70′ is arranged between eachretaining element 18, 18′ and the upper side 3 d of the pad back plate 3a and is pretensioned by the shape thereof and the arrangement betweeneach retaining element 18, 18′ and the respective recess of the upperside 3 d. Said pretensioning has the effect that each pad-retainingspring 70, 70′ rests with one end on the upper side 3 d of the pad backplate 3 a under pretension, wherein the other end protrudes over therespective end of the upper side 3 d in the longitudinal direction ofthe pad back plate 3 a and rests in a pretensioned manner on said end ofthe upper side 3 d when the brake pad 3 is not fitted.

Each pad-retaining spring 70, 70′ comprises a central section 70 a,transition sections 70 b and 70 c, at least one pressure section 71, 71′and at least one bearing section 72, 72′.

The exit-side pad-retaining spring 70 is described below. Theconstruction of the entry-side pad-retaining spring 70′ is ofmirror-inverted design.

A transition section 70 b, 70 c is attached to each end of the centralsection 70 a. The transition section 70 b faces towards one end of theupper side 3 d of the pad back plate 3 a and connects the centralsection 70 a to the pressure section 71. The transition section 70 c isattached on the other side of the central section 70 a, faces towardsthe center of the upper side 3 d and connects the central section 70 ato the bearing section 72. Each transition section 70 b, 70 c is shapedwith regard to the upper side 3 d in a manner curved towards the latter.

The lower side of the free end of the pressure section 71 has a contactsection 9 which, in the fitted state of the brake pad 3, rests on therest section 8 of the brake carrier horn 5 a. If the brake pad 3 is notfitted, the pressure section 71 rests on the end of the upper side 3 dof the pad back plate 3 a.

The lower side of the free end of the bearing section 72 has a restsection 72 a which rests continuously on the upper side 3 d of the padback plate 3 a.

The central section 70 a is arranged between the retaining element 18and a recess of the upper side 3 d of the pad back plate 3 a, whereinthe central section 70 a does not make contact with the upper side 3 d.This is made possible by the recess and also by the configuration of theretaining element 18 in the form of a cable roller.

The transition sections 70 b, 70 c span the central section 70 a, as aresult of which the pressure section 71 is pressed by the spring forceof the central section 7 a either onto the end of the upper side 3 d oronto the brake carrier horn 5 a. At the same time, the central section70 a which is tensioned in this manner has the effect that the bearingsection 72 is also pressed onto the upper side 3 d.

In this example, the pad-retaining springs 70, 70′ are produced from aspring wire material. In this case, the ends are correspondingly bentover in order to form the pressure section 71, 71′ and the bearingsection 72, 72′. Punctiform or/and curved contact sections are producedhere in interaction with the respective rest surfaces.

The brake pad 3 is installed as described in the first embodiment.

FIGS. 12-13 show partial views of a third embodiment of the disc brake 1according to the invention, wherein FIG. 12 shows a view of an actuationside 3 j of the pad back plate 3, as seen from the application side ZS(FIG. 1). FIG. 13 shows a view from the brake disc 2. FIG. 14 is aperspective view of a pad back plate 3 a of a brake pad 3 of the thirdembodiment according to FIGS. 12-13 onto the actuating side 3 j. FIG. 15is a perspective view of a pad-retaining spring 7 of the embodimentaccording to FIGS. 12-13. FIG. 16 illustrates a perspective view of afastening element 20 of the pad-retaining spring 7 according to FIG. 15of the brake pad 3 of the exemplary embodiment according to FIGS. 12-13.

In this third embodiment, the components of the disc brake 1 areidentical to those in the first embodiment except for the brake pad 3.Therefore, only the differences of the brake pad 3 are dealt with below.

The application-side brake pad 3 also has a pad back plate 3 a with afriction pad 3 b in this embodiment. The pad back plate 3 a is providedwith the contours which are already described above and correspond withcontours of the lugs 5 c, 5′c and undercuts 4, 4′.

In contrast to the first embodiment, the pad-retaining spring 7 isfastened in the center thereof to a fastening section 3 f by a fasteningelement 20. The fastening element 20 is described in more detail below.

In this third embodiment, the pad-retaining spring 7 includes a centralsection 7 a; arms 7 b, 7′b; pressure sections 7 c, 7′c and intermediatesections 7 e, 7′e.

The central section 7 a is provided with a slit 7 f running in thelongitudinal direction of the pad-retaining spring 7 for receiving asection of the fastening element 20. The slit 7 f does not run in animaginary central line of the pad-retaining spring 7, but rather runsoffset in the direction towards the friction pad 3 b and parallel to theimaginary central line of the pad-retaining spring 7. Said imaginarycentral line runs in the longitudinal direction of the pad-retainingspring 7.

In contrast to the first embodiment, a length of the central section 7 acorresponds approximately to half the length of the central section 7 aof the pad-retaining spring 7 of the first embodiment.

A respective arm 7 b, 7′b is attached to each end of the central section7 a. In contrast to the first embodiment, the arms 7 b, 7′b aresubstantially longer, for example in each case twice the length of thecentral section 7 a.

Each arm 7 b, 7′b is provided in the region of the free end thereof witha respective slit 7 g, 7′g. The slits 7 g, 7′g serve in each case forreceiving a guide projection 3 g, 3′g on upper side 3 d of the pad backplate 3 a.

A respective pressure section 7 c, 7′c is attached to each free end ofan arm 7 b, 7′b via an intermediate section 7 e, 7′e. Each intermediatesection 7 e, 7′e is bent downwards in a manner facing towards the upperside 3 d of the back plate 3 a at an obtuse angle here from therespective arm end. To this end, each pressure section 7 c, 7′c is bentupwards in the opposite direction on a respective free end of anintermediate section 7 e, 7′e. The pressure sections 7 c, 7′c eachextend laterally beyond the pad back plate 3 a and protrude from thelatter at a distance which approximately corresponds to an expansion ofa respective brake carrier horn 5 a, 5′a in the longitudinal directionof the pad back plate 3 a.

The fastening section 3 f protrudes from the upper side 3 d of the padback plate 3 a and has a continuous opening 19 which runs through thepad back plate 3 a in the direction of the brake disc rotational axis 2a. On that side of the pad back plate 3 a on which the friction pad 3 bis attached, the friction pad 3 b in the region of the opening 19 isrecessed below and next to the latter, as can be seen in FIG. 13.

The fastening element 20 (see FIG. 16) is designed here in the manner ofa clamp and comprises a plate 20 a, to the longitudinal sides of whichrespective trapezoidal side walls 20 b, 20 c are attached in each caseapproximately at a right angle. The trapezoidal side walls 20 b, 20 crun parallel and are connected at the short lower sides thereof by atransverse section 20 d. The transverse section 20 d is attached at aright angle to one side wall 20 b and is connected to the lower side ofthe other side wall 20 c at a connection 20 e, for example a weld seam.The transverse section 20 d runs parallel to the plate 20 a and, in themounted state of the pad-retaining spring 7, extends through the opening19. The connection 20 e is produced after the installation.

In the mounted state, the one trapezoidal side wall 20 b is guidedthrough the slit 7 f running in the longitudinal direction of thepad-retaining spring 7. A wider longitudinal section of the centralsection 7 a of the pad-retaining spring 7 is arranged here between theside walls 20 b, 20 c and between the lower side of the plate 20 a andthe upper side 3 d of the fastening section 3 f of the pad back plate 3a with a certain play in the radial direction with respect to the brakedisc rotational axis 2 a.

In the mounted state of the pad-retaining spring 7 on the upper side 3 dof the pad back plate 3 a, the guide projections 3 g, 3′g each extendthrough a slit 7 g, 7′g of the pad-retaining spring 7 and protrude fromthe upper side of each arm 7 b, 7′b. Contact sections 9, 9′ on the lowersides of the pressure sections 7 c, 7′c of the pad-retaining spring 7are each in contact here with an associated rest section 8, 8′, asalready described above.

In addition, in this embodiment, the pad back plate 3 a has upperbevelled corner sections 3 e, 3′e having a respective bevel 3 i, 3′i.Each bevel 3 i, 3′i merges via a recess 3 h, 3′h into a respective guideprojection 3 g, 3′g and into the upper side 3 d of the pad back plate 3a. The recesses 3 h, 3′h run from the respective bevel 3 i, 3′iinitially in a rectilinear section which then has a respective roundedportion in the transition to the respective guide projection 3 g, 3′gand the upper side 3 d.

FIGS. 17-18 illustrate partial views of a fourth embodiment of the discbrake 1 according to the invention, wherein FIG. 17 shows a view of theactuation side 3 j of the pad back plate 3, as seen from the applicationside ZS (FIG. 1). FIG. 18 shows a view of the pad back plate 3 a withoutfriction pad 3 b from the brake disc 2. FIG. 19 shows a perspective viewof the pad back plate 3 a of the brake pad 3 of the fourth embodimentaccording to FIGS. 17-18, as seen from the side of the friction pad 3 b.The friction pad 3 b is not shown here, but is easily imaginable. FIG.20 shows a perspective view of the pad-retaining spring 7 of theembodiment according to FIGS. 17-18.

In contrast to the third embodiment, the pad back plate 3 a does nothave a fastening section 3 f with an opening 19, but rather an upperside 3 d which is continuous between the guide projections 3 g, 3′g. Twoopenings 19, 19′ which are each arranged in the vicinity of a guideprojection 3 g, 3′g are provided in this fourth embodiment. A distanceof said openings 19, 19′ from each other is smaller here than a distanceof the guide projections 3 g, 3′g from each other.

In contrast to the third exemplary embodiment, the pad-retaining spring7 of the fourth exemplary embodiment is in each case fastened in the endregions of the central section 7 a to the pad back plate 3 a by afastening element 20, 20′. The fastening elements 20, 20′ are ofidentical design. A description in this regard has already been givenabove.

In this fourth embodiment, the pad-retaining spring 7 includes thecentral section 7 a; arms 7 b, 7′b; pressure sections 7 c, 7′c andintermediate sections 7 e, 7′e.

The central section 7 a is provided in the end regions thereof with arespective slit 7 f, 7′f running in the longitudinal direction of thepad-retaining spring 7 for receiving a section of a respective fasteningelement 20, 20′, as described above.

In contrast to the third embodiment, a length of the central section 7 acorresponds approximately to triple the length of the central section 7a of the pad-retaining spring 7 of the third exemplary embodiment and issomewhat shorter than the distance between the guide projections 3 g,3′g.

The arms 7 b, 7′b are respectively attached to each end of the centralsection 7 a. The arms 7 b, 7′b have a length which correspondsapproximately to half the length of an arm 7 b, 7′b in the thirdembodiment.

Each arm 7 b, 7′b is provided in the region of the free end thereof witha respective slit 7 g, 7′g. The slits 7 g, 7′g each serve for receivinga guide projection 3 g, 3′g.

The pressure sections 7 c, 7′c are in each case attached to each freeend of an arm 7 b, 7′b via an intermediate section 7 e, 7′e, as alreadydescribed in conjunction with the third embodiment.

The pad-retaining spring 7 is attached to the pad back plate 3 a by thefastening elements 20, 20′ in such a manner that the central section 7 aruns at a substantially constant distance from the upper side 3 d of thepad back plate 3 a.

A set of brake pads has the at least one application-side brake pad 3and at least one back-side brake pad. Said brake pads can also differ inlength.

The invention is not restricted by the above-described exemplaryembodiments, but rather can be modified within the scope of the attachedclaims.

For example, it is conceivable for the brake carrier 5 to be able to berealized with what is referred to as a radial groove 21 for simpleinstallation of the brake pad 3. The groove 21 extends in the directionof the respective brake carrier horn 5 a, 5′a between one side of theassociated lug 5 c, 5′c and an edge of the respective brake carrier horn5 a, 5′a. This is illustrated in FIG. 6.

FIGS. 21-22 shown another embodiment which provides for maintaining adesired level of pad-retaining spring preload in highly spacedconstrained environments. In the present invention, it is desirable tomaintain a lifting force on the brake pads, in particular the inboardbrake pad at all times following pad installation. For example, it maybe desired to maintain a lifting force on the order of 200-250 N. In theevent that this force must be maintained in a small available deflectionrange, for example 4 mm, a spring rate in the range of 50-65 N/mm wouldbe required. However, a commercial disc brake of the type of the presentinvention may have an assembly tolerance on the order of 2 mm. Such alarge tolerance could result in a pad-retaining spring having a 50-65N/mm spring rate having a spring preload that could vary as much as100-125 N, i.e., a variation that is greater than the 50 N tolerance ofthe desired 200-250 N preload range. Alternatively, if a pad-retainingspring with a lower spring rate were used, such as a 20 N/mm spring, thespring would have to deflect by between 10-12.5 mm to produce thedesired 200-250 N lifting force. Such a deflection distance could not betolerated in a space constrained environment.

FIG. 21 is a perspective view of an arrangement which can provide thedesired brake pad lifting force in a space-constrained environment. Inthis embodiment, after the application-side brake pad 3 is initiallyinstalled in the brake carrier mount pad slot, the pad-retaining spring7 is placed onto the upper surface 3 d of the application-side brake padback plate 3 a, with pad-retaining spring slots 7 g, 7 g′ engaging backplate projections 3 g, 3 g′ and pad-retaining spring outer ends 7 c, 7c′ resting on carrier mount horns 5 a, 5 a′. The pad-retaining spring 7is then pressed radially inward toward the upper surface 3 d of thebrake pad until a lift pin 75 can be inserted into an eye ring 3 k ofthe brake pad back plate 3 a that extends radially outward through aneye slit 7 h of the pad-retaining spring 7 (visible in the FIG. 22cross-section elevation view). Once the lift pin 75 is installed, it maybe secured in place, for example by a cotter pin 76. Preferably theforce required to compress the pad-retaining spring 7 a distancesufficient to insert the lift pin 75 is equal to the desired lift forcepreload, in this example a compressive force of 200-250 N.

The act of pressing radially inward to compress the pad retaining spring7 may be facilitated by use of the pad-retaining clip 10 as aninstallation tool. For example, in an embodiment in which thepad-retaining clip 10 is present an end of the clip may be partiallyinserted into a recess in the caliper application-side 6 a, then rotateddownward onto the upper surface of the pad retaining spring 7. Due tothe mechanical advantage provided by the length of the pad-retainingclip 10 as compared to the relatively short distance between the padretaining spring 7 and the recess in the caliper application-side 6 a,the spring 7 may be compressed with relative ease to a point at whichthe lift pin 75 can be inserted with little or no insertion force. Oncethe pin 75 is installed, the pad-retaining clip 10 may be released asthe pin 75 takes up the preloading force being applied to the spring. Ifthe pad-retaining clip 10 is then to be installed on the disk brake, itmay be removed from the recess in the caliper application-side 6 a andreoriented into the position in which it is installed when the brake isoperable.

With this arrangement, the pad-retaining spring preload is establisheddirectly between the spring, the brake pad back plate and the mounthorns, thereby substantially reducing or eliminating preload variationscaused by assembly tolerance stack-up. This arrangement also permits useof pad-retaining springs with spring rates on the order of 20 N/mm, asthe 10-12.5 mm of deflection required to establish a preload of 200-250N may be accommodated during compression of the spring during brake padinstallation, i.e., there is no need to be able to accommodate suchlarge spring deflections during assembled brake operation. Furtherbenefits of this spring preload arrangement include elimination ofreliance on a retainer clip as a part of the brake pad liftingstructure, although a retainer clip may still be present for otherpurposes, as shown in FIGS. 21 and 22. In these figures the retainingclip 10 is provided with a slot 10 b to accommodate the eye ring 3 k andlift pin 76.

Because such modifications of the disclosed embodiments incorporatingthe spirit and substance of the invention may occur to persons skilledin the art, the invention should be construed to include everythingwithin the scope of the appended claims and equivalents thereof.

LIST OF REFERENCE SIGNS

-   1 disc brake-   2 brake disc-   2 a brake disc rotational axis-   3 brake pad-   3 a pad back plate-   3 b friction pad-   3 c, 3′c projection-   3 d upper side-   3 e, 3′e corner section-   3 f fastening section-   3 g, 3′g guide projection-   3 h, 3′h recess-   3 i, 3′i bevel-   3 j actuation side-   3 k eye ring-   4, 4′ undercut-   5 brake carrier-   5 a, 5′a; 5 b, 5′b brake carrier horn-   5 c, 5′c lug-   5 d strut-   5 e fastening side-   5 f strut-   6 brake caliper-   6 a application section-   6 b reaction section-   6 c, 6′c connecting section-   7 pad-retaining spring-   7 a central section-   7 b, 7′b arm-   7 c, 7′c pressure section-   7 d, 7′d transition section-   7 e, 7′e intermediate section-   7 f, 7′f; 7 g, 7′g, h slit-   8, 8′ rest section-   9, 9′ contact section-   10 main direction of rotation-   10 a pivot point-   10 b slot-   11, 12 force-   11 a, 12 a lever arm-   13, 13′ undercut surface-   14, 14′ undercut surface-   15, 16 pad slot-   17, 17′ spring holder-   17 a projection-   18, 18′ retaining element-   19, 19′ opening-   20, 20′ fastening element-   20 a plate-   20 b, 20 c side wall-   20 d transverse section-   20 e connection-   21 groove-   70, 70′ pad-retaining spring-   70 a central section-   70 b, 70 c transition section-   71, 71′ pressure section-   72, 72′ bearing section-   72 a rest section-   75 lift pin-   76 cotter pin-   RS back side-   ZS application side

What is claimed is:
 1. A disc brake for a vehicle, comprising: a brakedisc having a brake disc rotational axis; a brake carrier configured tostraddle the brake disc; an application-side brake pad and a back-sidebrake pad with respective back plates configured to be supported on thebrake carrier in respective brake carrier pad slots; a brake caliperconfigured to straddle the brake disc while being supported on the brakecarrier in a manner that enables sliding of the brake caliper relativeto the brake carrier along a direction parallel to the brake discrotational axis; at least one pad-retaining spring coupled to theapplication side brake pad, wherein the brake carrier and at least theapplication side brake pad have form-fitting complementary contoursconfigured to constrain the application-side brake pad against radialmovement away from the brake disc rotational axis, and the at least onepad-retaining spring is configured to be supported at opposite ends onbrake carrier horns adjacent to the application-side brake carrier padslot and to exert a tensile force in a radially outward direction on theapplication-side brake pad.
 2. The disc brake according to claim 1,wherein the form-fitting complementary contours include opposing brakecarrier projections into the application-side brake carrier pad slot andcomplementary recesses in opposite lateral sides of the application-sidebrake pad.
 3. The disc brake according to claim 2, wherein undercutsurfaces of the contours of the brake carrier horns are configured toengage in a play-free manner undercut surfaces of projections of the padback plate located radially inward of the brake pad recesses.
 4. Thedisc brake according to claim 3, wherein the at least one pad-retainingspring is located on an upper side of the application-side brake padback plate.
 5. The disc brake according to claim 4, wherein the at leastone pad-retaining spring includes a central section, arm sectionsadjacent to opposite ends of the central section, pressure sectionsadjacent to the arm sections, and transition sections between thecentral section and the adjacent arm sections, and the central sectionis located on the upper side of the application-side pad back plate suchthat the transition sections contact the upper side of theapplication-side brake pad back plate and the pressure sections extendlaterally beyond the lateral sides of the application-side brake padback plate a distance sufficient to be supported on the brake carrierhorns.
 6. The disc brake according to claim 4, wherein the at least onepad-retaining spring includes a central section, arm sections adjacentto opposite ends of the central section, pressure sections adjacent tothe arm sections, and intermediate sections between the central sectionand the adjacent arm sections, and the central section is attached tothe application-side pad back plate by at least one fastening elementand the pressure sections extend laterally beyond the lateral sides ofthe application-side brake pad back plate a distance sufficient to besupported on the brake carrier horns.
 7. The disc brake according toclaim 6, wherein the at least one fastening element includes atransverse section extending through an opening in the application-sidebrake pad back plate and an upper section extending over thepad-retaining spring such that the pad-retaining spring passes betweenat least one fastening element and the upper side of theapplication-side brake pad back plate.